Communication System Radio Communication Terminal, and Radio Base Station

ABSTRACT

A wireless communication line is between a wireless base station and a wireless communication terminal, the base station includes a wireless base station transmission rate broadcast section that notifies the communication terminal of a transmission rate that enables support by the base station on the wireless communication line from the communication terminal to the base station, and the wireless communication terminal includes a storage section that stores a transmission rate required by the communication terminal on the communication line from the wireless communication terminal to the base station; a transmission rate comparison section that compares the transmission rate notified from the base station with the transmission rate stored in the storage section A transmission rate determination section determines a transmission rate on the communication line from the communication terminal to the base station based on a comparison result of the transmission rate comparison section.

TECHNICAL FIELD

The invention relates to a wireless communication system which performsdata communications, and more particularly, to a wireless communicationsystem wherein transmission rate in a radio zone can be changed.

BACKGROUND ART

In recent years, transmission capacity of a communication channel hasbeen increased in a mobile communication network too. In the mobilecommunication network, not only text data and HTTP data as in an e-mailbut also data whose amount is large such as picture or movie aretransmitted.

It is considered that data whose amount is large and which is requiredto transmit in real time will be bidirectionally transmitted forapplications such as IP telephone (VoIP) and videoconference in thefuture.

For example, a high speed communication network system using 1×EVDO (1×Evolution Data Only) system which is a mobile communication systemdedicated to data communications is proposed.

In the system, a wireless base station transmits packets to eachcommunication terminal being in the cover area of the wireless basestation. Each communication terminal measures link quality of a downlink(for example, CIR (Carrier-to-Interference Ratio)) based on a pilotsignal involved in reception packet.

Each communication terminal selects a communication mode wherein thecommunication terminal enables to perform high speed communications mostefficiently in the measured link quality. Each communication terminalfurther transmits DRC information (Data Rate Control signal)representing the selected communication mode to the wireless basestation.

The wireless base station refers to the DRC information transmitted fromeach communication terminal and allocates communication resourcespreferentially to the communication terminals with the better linkquality.

Accordingly, since data is transmitted to the communication terminalwith good link quality at a high transmission rate, required time forthe communication can be shortened. Since data is transmitted to thecommunication terminal with poor link quality at a low transmissionrate, error resilient can be enhanced.

The transmission rate of uplink (from wireless communication terminal towireless base station) in the 1×EVDO system is determined based on thestate of the wireless communication terminal and the wireless basestation and is controlled.

That is, the transmission rate of uplink in 1×EVDO is selected fromamong 9.6 kbps, 19.2 kbps, 38.4 kbps, 76.8 kbps, and 153.6 kbps. Theterminal sets the transmission rate of uplink to the lowest value 9.6kbps at the communication start time.

This value is updated according to the maximum transmission rateinformation in broadcast information sent from the wireless basestation.

That is, the transmission rate of the wireless communication terminal isset to 9.6 kbps in accordance with the maximum transmission rate justafter the operation is started after power of the wireless communicationterminal is turned on.

After communications are started, the wireless communication terminalperforms an update test of the transmission rate at a given periodwithin the range of the maximum transmission rate information sent fromthe wireless base station.

If the currently communicating wireless base station permits an increasein the transmission rate, the current transmission rate is maintained orcan make a transition to one higher step according to the result of thetransmission rate update test.

On the other hand, if the currently communicating wireless base stationdoes not permit an increase in the transmission rate, the currenttransmission rate is maintained or can make a transition to one lowerstep according to the result of the transmission rate update test.

FIG. 9 shows an example wherein the transmission rate of the wirelesscommunication terminal is changed in accordance with the algorithmdescribed above.

In the transmission rate in the related art shown in FIG. 9, the maximumtransmission rate of the wireless communication terminal is set to 9.6kbps at the communication start time. Therefore, the uplink transmissionrate is also 9.6 kbps.

Thereafter, the wireless communication terminal receives the broadcastinformation sent from the wireless base station, and the maximumtransmission rate of the wireless communication terminal is updated to153.6 kbps. But, the current transmission rate is maintained until thenext update timing.

If the wireless communication terminal succeeds in increasing thetransmission rate at the update timing, the transmission rate of thewireless communication terminal becomes 19.2 kbps which is the nexttransmission rate step to 9.6 kbps.

Then, if the wireless communication terminal fails increasing thetransmission rate, the current transmission rate is maintained. If thewireless communication terminal succeeds in increasing the transmissionrate, the transmission rate makes a transition to one higher step.

Thus, if the wireless base station permits a high transmission rate, theuplink transmission rate increases only stepwise.

Patent document 1: JP-A-2002-171213

However, in the determination method of the uplink transmission ratedescribed above, the communications are started at the lowesttransmission rate and the transmission rate is increased stepwise.

This system does not involve any problem in use of application whereinthe amount of data transmitted on the uplink is small such as WEBbrowsing or FTP downloading.

However, in application wherein a large amount of data is transmittedand a constant transmission rate is required also on the uplink such asIP telephone (VoIP) or videoconference, it takes time that the uplinktransmission rate reaches a speed required for the operation of theapplication. Thus, it takes time that the application can be used justafter starting communications.

For example, as shown in FIG. 9, if the operation of the applicationrequires the transmission rate 64 kbps or higher, the application cannotbe used until the transmission rate becomes 64 kbps or higher (arrivesat 76.8 kbps) after connection is established.

FIG. 10 shows a data communication sequence in the communication systemof the related art.

When a connection request is issued from an application (App) installedin a wireless communication terminal to the wireless communicationterminal (AT: Access Terminal), the connection request is sent from thewireless communication terminal to a wireless base station (AP: AccessPoint).

Then, after a wireless communication line is established between thewireless communication terminal and the wireless base station, theapplication transmits data to a server (Serv).

However, since the initial value of the uplink transmission rate of thewireless communication line between the wireless communication terminaland the wireless base station is set to 9.6 kbps, the data transmittedfrom the application via the wireless communication terminal and thewireless base station cannot be decoded in the server. Therefore, theapplication cannot normally operate.

Thereafter, even if the uplink transmission rate increases to 19.2 kbpsand 38.4 kbps, the application requiring the transmission rate 64 kbpsor higher cannot normally operate at the transmission rate 19.2 kbps,38.4 kbps.

Then, when the uplink transmission rate reaches 76.8 kbps, in theapplication requiring the transmission rate 64 kbps or higher, the datatransmitted from the application can be decoded in the server.Therefore, the application starts to operate normally.

Particularly, in the 1×EVDO system, maintaining the current transmissionrate or making a transition to one higher step is selected asprobability according to the result of the transmission rate updatetest.

Consequently, a time of about 10 seconds may be required by the time thetransmission rate increases from the initial value 9.6 kbps to 76.8 kbpsdepending on the result of the transmission rate update test. That is,time is required by the time the application starts to operate.

DISCLOSURE OF INVENTION

The object of the invention is to provide a communication system inwhich the uplink transmission rate rapidly increases from thecommunication start time to enable to use application rapidly.

A first invention is characterized in that by a wireless communicationsystem configured from a wireless base station and a wirelesscommunication terminal, wherein a wireless communication line is setbetween the wireless base station and the wireless communicationterminal, the wireless base station has: a wireless base stationtransmission rate broadcast section that notifies the wirelesscommunication terminal of a transmission rate that enables to besupported by the wireless base station on the wireless communicationline from the wireless communication terminal to the wireless basestation, and the wireless communication terminal has: a storage sectionthat stores a transmission rate required by the wireless communicationterminal on the wireless communication line from the wirelesscommunication terminal to the wireless base station; and a transmissionrate determination section that determines a transmission rate on thewireless communication line from the wireless communication terminal tothe wireless base station based on a result of comparing thetransmission rate notified from the wireless base station with thetransmission rate stored in the storage section.

A second invention is characterized by a wireless communication systemconfigured from a wireless base station and a wireless communicationterminal, wherein a wireless communication line is set between thewireless base station and the wireless communication terminal, thewireless communication terminal has: a terminal transmission ratebroadcast section that notifies the wireless base station of atransmission rate required by the wireless communication terminal on thewireless communication line from the wireless communication terminal tothe wireless base station when the wireless base station and thewireless communication terminal exchange their mutual state information;and a transmission rate determination section that determines atransmission rate on the wireless communication line from the wirelesscommunication terminal to the wireless base station, and the wirelessbase station has: a determination section that determines whether or notthe transmission rate notified from the wireless communication terminalenables to be supported; and a determination result broadcast sectionthat notifies the wireless communication terminal of a determinationresult of the determination section, wherein the transmission ratedetermination section determines the transmission rate on the wirelesscommunication line from the wireless communication terminal to thewireless base station based on the determination result notified fromthe wireless base station.

A third invention is characterized by the wireless communication systemaccording to the second invention, wherein the wireless communicationterminal notifies the wireless base station of the transmission raterequired by the wireless communication terminal on the wirelesscommunication line from the wireless communication terminal to thewireless base station when power of the wireless communication terminalis turned on, and determines the transmission rate on the wirelesscommunication line from the wireless communication terminal to thewireless base station based on the determination result notified fromthe wireless base station.

A fourth invention is characterized by the wireless communication systemaccording to the second or third invention, wherein the terminaltransmission rate broadcast section notifies the wireless base stationof a state information request message including the transmission raterequired by the wireless communication terminal on the wirelesscommunication line from the wireless communication terminal to thewireless base station.

A fifth invention is characterized by the wireless communication systemaccording to the any one of the second to fourth inventions, wherein thewireless communication terminal has a request transmission ratetransmission section that retransmits a request of a transmission ratelower than the transmission rate required by the wireless communicationterminal when the determination result from the wireless base stationsection shows that the transmission rate does not enable to besupported.

A sixth invention is characterized by a wireless communication terminal,wherein a wireless communication line is set between a wireless basestation and the wireless communication terminal, having: a storagesection that stores a transmission rate required by the wirelesscommunication terminal on the wireless communication line from thewireless communication terminal to the wireless base station; atransmission rate information acquisition section that receives atransmission rate that enables to be supported by the wireless basestation on the wireless communication line from the wirelesscommunication terminal to the wireless base station, notified from thewireless base station; a transmission rate comparison section thatcompares the transmission rate notified from the wireless base stationwith the transmission rate stored in the storage section; and atransmission rate determination section that determines a transmissionrate on the wireless communication line from the wireless communicationterminal to the wireless base station based on a comparison result ofthe transmission rate comparison section.

A seventh invention is characterized by a wireless communicationterminal, wherein a wireless communication line set between a wirelessbase station and the wireless communication terminal, having: a terminaltransmission rate broadcast section that notifies the wireless basestation of a transmission rate required by the wireless communicationterminal on the wireless communication line from the wirelesscommunication terminal to the wireless base station when the wirelessbase station and the wireless communication terminal exchange theirmutual state information; and a transmission rate determination sectionthat determines a transmission rate on the wireless communication linefrom the wireless communication terminal to the wireless base stationbased on a determination result as to whether or not the wireless basestation enables to support the transmission rate notified from thewireless communication terminal.

An eighth invention is characterized by the wireless communicationterminal according to the seventh invention, wherein when power of thewireless communication terminal is turned on, the wireless communicationterminal notifies the wireless base station of the transmission raterequired by the wireless communication terminal on the wirelesscommunication line from the wireless communication terminal to thewireless base station, and determines the transmission rate on thewireless communication line from the wireless communication terminal tothe wireless base station based on the determination result notifiedfrom the wireless base station.

A ninth invention is characterized by the wireless communicationterminal according to the seventh or eighth invention, wherein theterminal transmission rate broadcast section notifies the wireless basestation of a state information request message including thetransmission rate required by the wireless communication terminal on thewireless communication line from the wireless communication terminal tothe wireless base station.

A tenth invention is characterized by the wireless communicationterminal according to any one of the seventh to ninth inventions,having: a request transmission rate transmission section thatretransmits a request of a transmission rate lower than the transmissionrate required by the wireless communication terminal when thedetermination result from the wireless base station section shows thatthe transmission rate does not enable to be supported.

An eleventh invention is characterized by a wireless base station,wherein a wireless communication line is set between the wireless basestation and a wireless communication terminal, for performingcommunications, having: a wireless base station transmission ratebroadcast section that notifies the wireless communication terminal of atransmission rate that enables to be supported by the wireless basestation on the wireless communication line from the wirelesscommunication terminal to the wireless base station.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram to show the configuration of a wirelesscommunication system of an embodiment of the invention;

FIG. 2 is a sequence diagram of a communication system of a firstembodiment of the invention;

FIG. 3 is a schematic representation of the description of AccessParameters in the first embodiment of the invention;

FIG. 4 is a schematic representation of the description of AccessParameters in the first embodiment of the invention;

FIG. 5 is a schematic representation of the description ofReverseTrafficChannelStart (uplink speed information) in the firstembodiment of the invention;

FIG. 6 is a sequence diagram of a communication system of a secondembodiment of the invention;

FIG. 7 is a schematic representation of the description of ConfigurationResponse in the second embodiment of the invention;

FIG. 8 is a flowchart of a transmission rate determination processing ofthe embodiment of the invention;

FIG. 9 is a schematic representation of change in uplink transmissionrate according to the embodiment of the invention; and

FIG. 10 shows a sequence diagram of a communication system in a relatedart.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the invention will be described with reference to theaccompanying drawings.

FIG. 1 is a block diagram to show the configuration of a wirelesscommunication system of an embodiment of the invention.

A wireless communication terminal 10 is connected to a server 20 througha wireless base station 30. Data required to transmit in real time istransmitted and received between the wireless communication terminal 10and the server 20. Application requiring real-time processing such as IPtelephone or streaming is operated in both of the wireless communicationterminal 10 and the server 20.

The wireless communication terminal 10 is a mobile telephone or a PDA(Personal Digital Assistant) capable of performing data communications,a computer to which a data communication card involving a radio isadded, or the like.

The wireless communication terminal 10 has an antenna 11 for receiving aradio wave (downlink signal) sent from the wireless base station 30 andtransmitting a radio wave (uplink signal) to the wireless base station30. The antenna 11 is connected to a radio section 12.

The radio section 12 has a transmission section and a reception section.The transmission section generates a high-frequency signal to betransmitted from the antenna 11. The reception section executesamplification, frequency conversion, etc., of the high-frequency signalreceived by the antenna 11 to output as a baseband signal to atransmission-reception section 13.

The transmission-reception section 13 includes a modem circuit and aCODEC section. The baseband signal is demodulated by a demodulationcircuit.

The demodulated signal is sent to the CODEC section, and is then decodedinto a data signal by the CODEC section.

The CODEC section also codes the data signal. The coded signal is sentto the modem circuit, and is then modulated by the modem circuit.

The modulated signal is converted into a high-frequency signal by theradio section (transmission section) 13. The high-frequency signal istransmitted from the antenna 11.

The data processed by the transmission-reception section 13 is sent toan application processing section 14.

In the application processing section 14, a program requiring thereal-time processing such as IP telephone operates and processes thedata processed by the transmission-reception section 13 in real time andsends the data to a voice input/output section 15 for output as a voicesignal.

A voice signal input to the voice input/output section 15 is processedin real time by the program operating in the application processingsection 14 and is sent to the transmission-reception section 13, whichthen transmits the signal to the server 20 through the radio section 12and the antenna 11.

A control section 17 controls each section of the wireless communicationterminal 10 such as the radio section 12 and the transmission-receptionsection 13.

Specifically, the control section 17 controls the transmission-receptionfrequency and the transmission-reception timing with a channel specifiedfor the radio section 12.

The control section 17 generates various control signals of setting,releasing, position registration, etc., of the wireless communicationline between the wireless communication terminal 10 and the wirelessbase station 30 in accordance with a predetermined communicationprotocol. The control section 17 controls transmission and reception ofthe signals.

Further, since the wireless communication network is a 1×EVDO network inthe embodiment of the invention, the wireless communication terminal 10transmits DRC information which is a signal indicating a communicationmode selected as the mode capable of efficiently performing datacommunications based on the CIR found by receiving a signal transmittedfrom the wireless base station 30 (for example, a pilot signal, acontrol packet, etc.,) to the wireless base station 30 as wirelesscommunication link quality information.

The wireless communication terminal 10 determines the transmission rateof the wireless communication line (uplink) to the wireless base station30 based on the state of the wireless communication terminal 10 and thewireless base station 30.

The wireless base station 30 has an antenna 31 connected to a radiosection and receives a radio wave (uplink signal) sent from the wirelesscommunication terminal 10 and transmits a radio wave (downlink signal)to the wireless communication terminal 10.

The radio section has a transmission section and a reception section.The transmission section generates a high-frequency signal to betransmitted from the antenna 31. The reception section executesamplification, frequency conversion, etc., of the high-frequency signalreceived by the antenna 31 to output as a baseband signal to atransmission-reception section.

The transmission-reception section includes a modem circuit and a CODECsection. The baseband signal is demodulated by a demodulation circuit.

The demodulated signal is sent to the CODEC section, and is then decodedinto a data signal by the CODEC section.

The CODEC section also codes the data signal. The coded signal is sentto the modem circuit, and is then modulated by the modem circuit.

The modulated signal is converted into a high-frequency signal by thetransmission section. The high-frequency signal is transmitted from theantenna 31.

An interface section is connected to the transmission-reception section.The radio base station 30 is connected to a network such as the Internetthrough the interface section.

The wireless base station 30 includes a control section for controllingeach section of the wireless base station 30 (the radio section, thetransmission-reception section, the interface section, etc.,).

Specifically, the control section controls the transmission-receptionfrequency and the transmission-reception timing with a channel specifiedfor the radio section.

In response to a connection request from the wireless communicationterminal, the control section controls permission and inhibition of theconnection and the number of connected wireless communication terminals.

Further, since the wireless communication network is a 1×EVDO network inthe embodiment of the invention, the wireless base station 30 determinesthe data communication bandwidth allocated to each client, anddetermines the transmission rate of the wireless communication line(downlink) to the wireless communication terminal 10, based on thequality information of the wireless communication transmitted from thewireless communication terminal 10 and the number of connected wirelesscommunication terminals.

The server 20 is an apparatus with which the wireless communicationterminal 10 communicates. A program corresponding to the applicationprogram operating in the wireless communication terminal 10 operates inthe server 20.

The data sent from the wireless base station 30 through the interfacesection is sent to an application processing section 24.

In the application processing section 24, a program requiring thereal-time processing such as IP telephone operates and processes thedata sent from the wireless base station 30 in real time and sends thedata to a voice input/output section 25 for output as a voice signal.

A voice signal input to the voice input/output section 25 is processedin real time by the program operating in the application processingsection 24 and is sent to the wireless base station 30, which thentransmits the signal to the wireless communication terminal 10 throughthe wireless base station 30.

FIG. 2 is a sequence diagram of the communication system of the firstembodiment of the invention, and shows processing at the communicationstart time.

The wireless communication terminal (AT: Access Terminal) 10 receivesaccess parameters (Access Parameters) transmitted at a predeterminedtiming from the wireless base station (AP: Access Point) 30 while thewireless communication terminal 10 is operating.

The access parameters involves information concerning the state of thewireless base station (function of the wireless base station, linetraffic state, etc.,).

In the wireless communication system of the embodiment of the invention,the wireless communication terminal receiving the access parametersrefers to the uplink transmission rate that can be supported by thewireless base station involved in the access parameters, in order to setthe uplink transmission rate to the required transmission rate in therange that can be supported by the wireless communication terminal.

For example, if 153.6 kbps is indicated in the access parameters, theuplink transmission rate is selected in the range up to 153.6 kbps bythe operating application.

When a connection request is issued from an application program (App)operating in application processing section 14 installed in the wirelesscommunication terminal to the wireless communication terminal, theconnection request (Connection Request) is transmitted from the wirelesscommunication terminal to the wireless base station.

In response to the request, the wireless base station specifies acommunication channel (Traffic Channel Assignment), and the wirelesscommunication terminal sets the communication channel and transmits aresponse signal (Traffic Channel Complete) to establish thecommunication channel.

Then, the wireless communication terminal requires a communication portin the communication channel (Xon Request), and the wireless basestation specifies a communication port (Xon Response) and decides thecommunication port.

Then, user authentication, etc., is performed in a data link layeraccording to LCP Configuration, the communication function in a networklayer is set according to SN Authentication and IPIC Configuration, PPP(Point to Point Protocol) is set, and the communication between theapplication and the server (Serv) 20 is established.

When the application is started, data is sent at speed of 64 kbps fromthe application to the wireless communication terminal because theapplication requires the transmission rate 64 kbps.

The wireless communication terminal transmits data at speed of 76.8 kbpsto the wireless base station.

The uplink data speed is described in the header portion of a datapacket transmitted from the wireless communication terminal to thewireless base station. The wireless base station which have received thedata packet from the wireless communication terminal refers to theheader of the data packet to identify the transmission rate of thepacket.

The wireless base station transmits data to the server at the speed 76.8kbps.

An application program requiring the transmission rate 64 kbps operatesin the application processing section 24 of the server. The data is sentat the transmission rate 76.8 kbps from the wireless communicationterminal to the server. Thus, the data can be decoded in the server andthe application can operate normally.

FIGS. 3 and 4 show the description of the access parameters (AccessParameters) in the first embodiment of the invention.

As shown in FIG. 3, the access parameters are provided with an attributerecord area (Attribute Record) following a message ID (Message ID) and atransaction ID (Transaction ID).

As shown in FIG. 4, the attribute record area involves length ofattribute record area (Length), attribute ID (Attribute ID), and uplinkspeed information (ReverseTrafficChannelStart). The uplink speedinformation indicates the transmission rate of the uplink.

FIG. 5 shows the description of the uplink speed information(ReverseTrafficChannelStart) in the first embodiment of the invention.

Codes are defined for the uplink transmission rates (9.6 kbps, 19.2kbps, 38.4 kbps, 76.8 kbps, and 153.6 kbps) that can be adopted in the1×EVDO system. The wireless communication terminal 10 receiving acontrol message containing ReverseTrafficChannelStart can extract thecode to obtain the uplink transmission rate information that can besupported by the wireless base station 30.

FIG. 6 is a sequence diagram of a communication system of a secondembodiment of the invention, and shows processing when power of awireless communication terminal is turned on.

When the wireless communication terminal (AT: Access Terminal) 10 startsto operate as power is turned on, the wireless communication terminal 10transmits a connection request (Connection Request) to a wireless basestation.

In response to the request, the wireless base station specifies acommunication channel (Traffic Channel Assignment), and the wirelesscommunication terminal sets the communication channel and transmits aresponse signal (Traffic Channel Complete) to establish thecommunication channel.

Then, the wireless communication terminal transmits informationreporting information of the state of the wireless communicationterminal (function of wireless communication terminal, etc.,)(Configuration Response) and requests the wireless base station to sendinformation of the state of the wireless base station (ConfigurationRequest).

In response to the request, the wireless base station sends informationof the state of the wireless base station (function of the wireless basestation, line traffic state, etc.,) (Configuration Response). Thewireless communication terminal which have received ConfigurationResponse transmits an acknowledge signal (Configuration Complete), andthe wireless base station also transmits an acknowledge signal(Configuration Complete).

Upon reception of Configuration Complete, the wireless communicationterminal transmits a Connection Close signal for disconnecting the linebecause exchange of the state information (parameters) between thewireless communication terminal and the wireless base station iscompleted.

In the wireless communication system of the embodiment of the invention,the wireless communication terminal receiving Configuration Responsesets the transmission rate to the uplink transmission rate requested inConfiguration Request if Configuration Response is informationindicating the supportable range. For example, if 153.6 kbps isrequested in Configuration Request, the uplink transmission rate isselected in the range up to 153.6 kbps by the application whichoperates.

When a connection request is issued from an application (App) 14operating in the wireless communication terminal installed in thewireless communication terminal to the wireless communication terminal,the connection request (Connection Request) is transmitted from thewireless communication terminal to the wireless base station.

In response to the request, the wireless base station specifies acommunication channel (Traffic Channel Assignment), and the wirelesscommunication terminal sets the communication channel and transmits aresponse signal (Traffic Channel Complete) to establish thecommunication channel.

Then, the wireless communication terminal requires a communication portin the communication channel (Xon Request), and the wireless basestation specifies a communication port (Xon Response) and selects thecommunication port.

Then, user authentication, etc., is performed in a data link layeraccording to LCP Configuration, the communication function in a networklayer is set according to SN Authentication and IPIC Configuration, PPP(Point to Point Protocol) is set, and the communication between theapplication and the server (Sere) 20 is established.

When the application is started, data is sent at speed of 64 kbps fromthe application to the wireless communication terminal because theapplication requires the transmission rate 64 kbps.

The wireless communication terminal transmits data at speed of 76.8 kbpsto the wireless base station.

The uplink data speed is described in the header portion of a datapacket transmitted from the wireless communication terminal to thewireless base station. The wireless base station which have received thedata packet from the wireless communication terminal refers to theheader of the data packet to identify the transmission rate of thepacket.

The wireless base station transmits data to the server at the speed 76.8kbps.

An application program requiring the transmission rate 64 kbps operatesin the server. The data is sent at the transmission rate 76.8 kbps fromthe wireless communication terminal. Thus, the data can be decoded inthe server and the application can operate normally.

FIG. 7 shows the description of Configuration Response in the secondembodiment of the invention.

Configuration Response to be transmitted as the state information of thebase station is provided with an area describing informationrepresenting the state of the wireless base station following a messageID (Message ID).

The area involves information (RTCStartRateChangeEnabled) as to whetheror not uplink speed information is involved and uplink speed information(ReverseTrafficChannelStart). The description of the uplink speedinformation (ReverseTrafficChannelStart) is defined like that in thefirst embodiment (FIG. 5).

FIG. 8 is a flowchart of a transmission rate determination processing ofthe embodiment of the invention.

At first, the wireless communication terminal 10 receives a broadcastmessage and extracts RTCStartRateChangeEnabled (information as towhether or not uplink speed information is involved) andReverseTrafficChannelStart (uplink speed information) involved in thebroadcast message (S101).

Whether or not uplink speed information is involved in the broadcastmessage is determined (S102).

That is, if the value of RTCStartRateChangeEnabled is 0, uplink speedinformation is not involved in the broadcast message. Therefore, in thiscase, the initial value of the uplink transmission rate is set to thelowest value 9.6 kbps (S103).

On the other hand, if the value of RTCStartRateChangeEnabled is not 0,uplink speed information is involved in the broadcast message.Therefore, in this case, ReverseTrafficChannelStart (uplink speedinformation) involved in the broadcast message and the transmission raterequired by the wireless communication terminal 10 are compared (S104).

If the transmission rate required by the wireless communication terminal10 is greater than ReverseTrafficChannelStart, the initial value of theuplink transmission rate is set to the value defined inReverseTrafficChannelStart (S105).

On the other hand, if the transmission rate required by the wirelesscommunication terminal 10 is equal to or less thanReverseTrafficChannelStart, the initial value of the uplink transmissionrate is set to the transmission rate required by the wirelesscommunication terminal 10 (S106).

When the initial value of the uplink transmission rate is determined,connection of data communications is established (S107) and datacommunications are started.

While the invention has been described in detail with reference to thespecific embodiments, it will be obvious to those skilled in the artthat various changes and modifications can be made without departingfrom the spirit and the scope of the invention.

The present application is based on Japanese Patent Application (No.2002-357977) filed on Dec. 10, 2002, which is incorporated herein byreference.

INDUSTRIAL APPLICABILITY

According to the invention, the uplink transmission rate can be set tohigh speed (for example, 76.8 kbps) from the beginning of communicationsfor transmitting data, and an application program requiring a hightransmission rate can be used from the communication start time.

As the start speed of the uplink data communications is changed,unnecessary data is not transmitted. Therefore, the whole throughput ofthe system can be improved.

Since the uplink transmission rate can be previously determined beforecommunications are started, use of application can be started promptly.

The sequence for determining the uplink transmission rate is notcomplicated.

Since the uplink transmission rate can be determined under theinitiative of the wireless communication terminal, the uplinktransmission rate is not set to a speed where the application operatingin the wireless communication terminal cannot be used.

Since the uplink transmission rate can be determined under theinitiative of the wireless communication terminal, the load on thewireless base station can be decreased.

1-11. (canceled)
 12. A wireless communication system configured from awireless base station and a wireless communication terminal, thewireless base station comprises: a notify section that notifies awireless communication terminal of an initial uplink transmissionresources which the wireless communication terminal uses; and thewireless communication comprises: an obtaining section that obtains theinitial uplink transmission resources; and a transmission section thattransmits data corresponding to the obtained uplink transmissionresources.
 13. A wireless communication terminal comprises: an obtainingsection that obtains an initial uplink transmission resources from awireless base station; and a transmission section that transmits dataobtained corresponding to the obtained initial uplink transmissionresources.
 14. A wireless base station for performing communications,comprising: notify section that notifies a wireless communicationterminal of an initial uplink transmission resources which the wirelesscommunication terminal uses; and wherein the wireless communicationterminal can obtain the initial uplink transmission resources.
 15. Amethod of a wireless communication system configured from a wirelessbase station and a wireless communication terminal the wireless basestation comprises: a notifying the wireless communication terminal of aninitial uplink transmission resources, and the wireless communicationterminal comprises: obtaining the initial uplink transmission resourcesfrom the wireless base station; and transmitting data corresponding tothe obtained initial uplink transmission resources.